Your body has powerful microscopic armed forces to combat germs.  Billions of white blood cells vigilantly patrol through the blood stream.  Special fighting units, cells in your bloodstream called macrophages (Greek for big eaters) attack germs by surrounding them and digesting them.  Other cells make powerful chemicals called antibodies.  They are anti, or against, these foreign bodies and attack the outsides of germs.  They team with other specialized germ fighters called T cells.

Each kind of germ has an outer layer that's different than those on other germs. Antibodies your body produced to fight off last year's flu virus can't get a grip on this year's model.  So your immune system has to go back to the drawing board and make new antibodies.  But the good news is germs can't fool your immune system twice.  Once your body has withstood an attack by a specific germ, the antibody making cells remain on alert. They're ready to rumble if the same germs show up again.

Last but not least, your immune system makes the almighty fighter interferon.  It interferes with invading viruses trying to replicate themselves inside your cells. Interferon also helps activate macrophages and other immune defenses, including natural killer cells (cells that detect and start killing tumor cells) even before antibodies attach to their outsides, providing a crucial and early assault.

You're immune system may be complex, but some simple lifestyle habits can help keep it strong.  A healthful diet, exercise, supplements, lowering stress, and more can make a difference in maintaining a healthy immune system.  Take care of your immune system, so it can take care of you.

Having said that, there's still much you can do to stay strong and healthy all winter.  Talk to your doctor about the best ways to protect yourself and give these prevention strategies a try:

1. Wash Your Hands:  Washing hands remains the most effective way to protect yourself and your family from colds and flu. Lather, rinse, repeat throughout the day. Do it long enough to sing "Happy Birthday" twice.
2. Get Enough Sleep:  Sleep may be your immune system's secret weapon, according to recent scientific research.  Less than seven hours of sleep a night made people three times more likely to catch a cold than those who got eight or more hours of zzzs.
3. Exercise:  While very vigorous physical activity (like running a marathon) can put a damper on your immune system, most scientists agree that moderate physical activity actually helps boost the immune cells that fight off invaders.
4. Fuel Yourself with Good Nutrition:  An orange a day (along with strawberries, bell peppers, potatoes, and other vitamin C rich fruits and vegetables) can help keep the doctor away.  Lean meat, fish, and other protein sources also provide the amino acids needed to help maintain your immune system. Don't forget to fill in nutritional gaps with immune supporting nutrients like zinc and vitamins D, A, C and E.  Harvard scientists even suggest vitamin D supplements may help reduce the occurrences of colds.  The scientists found low vitamin D levels in nearly 20,000 Americans increased their cold and flu risk.
5. Power up with Plant Extracts:  Scientific research has led to the discovery of a combination of plant extracts that naturally boost the body's own production of interferon, a component of the immune system that helps fight off viruses.  Other plant compounds found in elderberry and echinacea extracts can help, too.  Take these when you feel the first sign of something coming on, and continue taking them for about a week as needed.